Suppression of resist pattern collapse by crosslinker in ultraviolet nanoimprinting involving sequential infiltration synthesis with trimethylaluminum

The fabrication of resist patterns using UV nanoimprinting is required on consideration of the reduction of the use of hydrocarbons along recent amendments for environmental sustainability. In this study, we investigated the generation of resist pattern defects through UV nanoimprinting in a readily condensable trans-1,3,3,3-tetrafluoropropene (TFP) gas with a low global warming potential for elimination of nonfill defects arising from a bubble trap and subsequent sequential infiltration synthesis (SIS) to result in a vapor phase organic-inorganic hybridization for dry etching durability. A bisphenol A-based UV-curable imprint resin enabled the nanostructure fabrication of resist patterns without any nonfill defects in TFP; however, SIS consisting of subsequent mutual doses of trimethylaluminum and water caused a resist pattern collapse of 100-nm-height patterns with linewidths of <60 nm. A crosslinker with six acrylate moieties was selected based on its low TFP absorption. The crosslinker-containing imprint resin decreased the resist pattern collapse during SIS. Nanoindentation measurements suggest that the resist patterns made using the crosslinker-containing imprint resin were strengthened at 100 °C to carry out an SIS.